WALLOPS ISLAND, Va. — A new private rocket called Antares is
poised to blast into space for the first time today, potentially
marking a giant leap forward for the emerging commercial
spaceflight industry.

The
Antares rocket is slated to lift off at 5 p.m. EDT (2100 GMT)
Wednesday (April 17) from Virginia's Mid-Atlantic Regional
Spaceport (MARS), on a test flight designed to pave the way for
unmanned cargo missions to the International Space Station.

If all goes well today, two different private American spacecraft
could soon be delivering supplies to the orbiting lab for NASA —
a scenario the agency envisioned five years ago, when it signed
billion-dollar cargo deals with SpaceX and Antares' builder,
Virginia-based Orbital Sciences Corp. [ How
to see the Antares rocket launch ]

"A lot of people say that the American space program is in
decline," Phil McAlister, NASA's director of commercial
spaceflight development, said Tuesday (April 16) from the
agency's
Wallops Flight Facility, where MARS is located. "Well, you
only have to go a couple of miles down the road to see it on the
rise, literally."

Today's test flight will mark the biggest rocket ever to fly from
Virginia's Eastern Shore and Wallops Island, which is NASA's
launching ground for small sounding rockets. The launch could be
visible from a wide swath of the U.S. East Coast, reaching as far
north as Portland, Maine, and as far south as Charleston, S.C.
You can watch the
Antares launch webcast live here at SPACE.com, courtesy of
NASA.

"This is a big event for the Eastern Shore for Wallops, and for
everybody in the surrounding area and, I think, for everybody in
the country," Orbital executive vice president Frank Culbertson,
general manager of Orbital's advanced programs group, told
reporters Tuesday.

NASA is counting on Orbital and SpaceX to fill the cargo-carrying
void left by the retirement of the agency's space shuttle fleet,
which was retired in 2011 after 30 years of spaceflight.

Orbital signed a $1.9 billion contract with NASA to fly eight
unmanned supply missions using Antares and a spacecraft called
Cygnus under the space agency's Commercial Resupply Services
program. California-based SpaceX got $1.6 billion for 12 flights
with its
Falcon 9 rocket and Dragon capsule.

SpaceX has
already flown two of these contracted missions, delivering cargo
to the orbiting lab in October 2012 and then again this past
March. Dragon also visited the station on a demonstration flight
in May of last year.

Orbital plans to be up and running soon as well. NASA picked
Orbital as one of its cargo carriers in 2008 under a separate
Commercial Orbital Transportation Service program, awarding the
company $288 million to help develop the Cygnus spacecraft. At
the time, Orbital was developing the Antares rocket in-house and
added several hundred million of its own funds for the project,
company officials said. [ Orbital's
Antares Rocket Explained (Infographic) ]

Orbital
Sciences is already prepping a Cygnus for a demonstration
mission to the space station, which could blast off by late June
if today's Antares launch goes smoothly. The first official
Cygnus cargo mission could then follow by year's end.

"It's being sent off to the fueling facility to get fueled,
because the cargo's already packed," said Orbital spokesman
Barron Beneski, explaining that Cygnus will carry about a
half-load of cargo up to the station on its maiden voyage.

The progress made by both SpaceX and Orbital shows that NASA's
decision to rely on commercial cargo providers was a good one,
Beneski added.

"I think it validates the approach that NASA has taken," he told
SPACE.com. "For the government, I think this is a very good
business deal on their part."

NASA also wants private American spaceships to start carrying its
astronauts to and from the orbiting lab by 2017, ending its
current reliance on Russian Soyuz spacecraft for this taxi
service.

SpaceX is working on a manned version of Dragon in the hopes of
scoring a NASA crew contract. Other major contenders are Boeing
and Sierra Nevada Corp., which are developing a capsule called
the CST-100 and a space plane called Dream Chaser, respectively.

"I think what this shows you is that there's no one way to do
spaceflight development. There's no one business case," McAlister
said. "There are multiple approaches and multiple strategies and
philosphies that can work. We have this competitive environment
and they are free to innovate."

From start to finish, today's test flight will last about 18
minutes. It should take the
Antares rocket, however, about 10 minutes to deploy its
payload — a dummy version of the Cygnus spacecraft — after
launch.

While Orbital is targeting a 5 p.m. EDT (2100 GMT) liftoff, the
company has a three-hour window in which to launch the Antares
rocket. Currently, there is about a 45 percent chance of good
weather at launch time. The potential for thick low clouds — NASA
has a visibility requirement for the flight — and rainstorms are
the only concerns. Orbital would try again on Thursday (April 18)
if weather delays today's flight.

The Antares rocket is a two-stage booster that stands about 131
feet (40 meters) tall and is powered by two Aerojet AJ26
liquid-fueled engines that are modernized versions of engines
originally built to launch Russia's N-1
moon rocket in the 1960s.The second stage is a solid-fueled
rocket motor built by Alliant Techsystems (ATK), the same company
that built the rocket boosters for NASA's space shuttles.

The rocket, Culbertson said, will appear to take its time
launching off the pad before streaking spaceward on a
southeastern trajectory that carries it out over the Atlantic
Ocean. Since the launch will be visible from Washington, D.C.,
Orbital officials have provided viewing guides to members of
Congress to help lawmakers see the launch, and will host an event
at the company's office near the Capitol.

"'My confidence level is very high," Culbertson said. "I think
we're going to see a nice show and I feel great."

The target orbit of the Antares rocket is a path that alternates
between 155 miles (250 kilometers) and 188 miles (303 kilometers)
above the Earth. The dummy Cygnus vehicle should stay in orbit
for about two weeks before burning up in Earth's atmosphere,
Culbertson said.

Before burning up, however, the Cygnus mass simulator will deploy
several tiny satellites for NASA and a commercial client. The
small nanosatellites include two versions of
coffee cup-size Phonesats for NASA's Ames Research Center and
the Dove-1 nanosatellite for a commercial customer.

Culbertson said today's launch will likely be the loudest rocket
ever to blast off from Wallops Island, which is flanked by a
national wildlife refuge.

"We'll try not to disturb the crabs and oysters," he said with a
laugh.

Editor's note: If you snap a great photo of
Orbital's Antares rocket launch that you'd like to share for
a possible story or image gallery, send photos, comments and your
name and location to managing editor Tariq Malik at spacephotos@space.com.